The invention relates to a dynamo-electric machine comprising a laminated stator and a laminated rotor and one or more winding systems.
As a result of the winding systems generally arranged in grooves of a laminated element, dynamo-electric machines have winding overhangs on the end faces of the laminated stator and/or laminated rotor. These winding overhangs are produced by the diversion of the electrical conductors of the winding system on the end faces of the laminated stator and/or laminated rotor. Above all in the area of the winding overhangs the electrical conductors are in contact with electrical conductors of adjacent electrical phases via the insulation. This insulation can be damaged by insulation faults, caused for example by overtemperatures or overvoltages and an interturn fault occurs in the winding overhang and/or groove area.
The development of heat and/or noise resulting from the interturn fault, as well as any further torque of the motor that will occur can represent a possible danger for the operating personnel or for the dynamo-electric machine. Therefore an interturn fault must be recognized in good time, in order to enable suitable measures to be initiated where necessary.
With electrically driven vehicles with a number of electric motors for example the vehicle will continue to be operated, even when there is a defect in a drive or in a motor. In such cases the defective motor will as a rule be disconnected from the energy supply. If there is an interturn fault in the defective motor the speed of the vehicle or the rotational speed of the defective motor that thus exists will mean that electrical energy continues to be fed into the location of the fault. Disconnection from the electrical supply makes it more difficult to recognize or to trace an interturn fault however. Depending on the severity of the possible consequences of the fault, a detected interturn fault can have significant effects on the operational management of such vehicles.
Under some circumstances in such cases this involves a reduction in the speed or even this vehicle coming to a standstill. Recognition of interturn faults must therefore be very reliable. Above all it may not result in any false triggers. Also only serious interturn faults with critical effects should be recognized, in order not to disrupt the operation of the vehicle.
The following methods for detection of interturn faults are currently known. The use of temperature sensors involves the disadvantage of the interturn fault having to be in the direct vicinity of the sensor. If the motor is comparatively well cooled, an interturn fault may possibly not be detected via temperature sensors.
Likewise a diagnosis via the converter currents is possible, in which case the short circuit to ground or non-symmetry of the motor currents is detected by the control software of the converter and it is concluded that there is an interturn fault.
The disadvantage here is that, with this protection concept, the converter disconnects itself from the motor in the event of a motor fault. When the converter is disconnected from the motor however an interturn fault of the motor can no longer be recognized by the control software.